The proposed research has the objective of applying a multivariate event time-series analysis to the study of cigarette-smoking and coffee-drinking interactions. Event time-series dependencies between the occurrences in time of instances of cigarette smoking and coffee drinking will be investigated in relationship to concurrent environmental conditions. Observations of such instances of cigarette smoking and coffee drinking will be undertaken during 10-day residences of 3-person groups in a programmed environment which provides for continuous and comprehensive assessment of individual and social behaviors in relationship to a broad range of environmental circumstances (e.g., work, leisure, learning, eating, socializing, etc.) typically involved in everyday life pursuits. Multivariate time-series analyses will be employed (1) to assess the dependencies between series of cigarette smoking and coffee drinking under conditions involving abstinence and/or dose manipulations of such commonly used substances, and (2) to assess the dependencies among series of cigarette smoking, coffee drinking, and programmed environment activity events under conditions of ad libitum substance use. A knowledge of the major interactive influences of common pharmacological and situational variables as they affect cigarette smoking behavior, combined with multivariate characterizations of individual smoking patterns, may be anticipated to permit a more powerful assessment of the relationship of such factors to the efficacy of treatment programs intended to modify cigarette smoking.